According to the present invention, there is provided a semi-submerged vessel in hydro dynamic shape similar to a torpedo to reduce the resistance when pushed through water, the concept of a semi-submerged transport system is not new as shown in reference by H. M. Combo U.S. Pat. No. 2,727,485 Dec. 29, 1955 and Joseph F. Schirtzinger U.S. Pat. No. 3,868,930 Mar. 4, 1975. All these designs have failed to take the advantage of a heavy mass in motion to produce energy, additionally the danger factor of sinking is increased so therefore no substantial benefit is obtained, not so with the present invention. The ability to rotate a Cargo Torpedo makes this design superior by reducing the cost of fuel, increasing the safety factor and can mix large amounts of liquid without additional costs and finally the prime mover of the vessel can be engaged and disengaged which reduces harbor expense. In order to have the Cargo Torpedo rotating a stud at the center of stern of cargo vessel is joined into the bow of a prime mover vessel which propels the cargo vessel, meaning the cargo vessel is pushed against the sea current by attached prime mover vessel. The rotation of the cargo vessel is introduced by fins installed around the circumference of the cargo vessel with a corrugated surface to take advantage of sea current when confronted from the side. The rotation of the vessel is transmitted to an alternator installed on the inside of the prime mover vessel to produce electricity which in return is used to supply the prime-mover with energy. The prime mover can be an engine of any design, but a fluid heat engine becomes most practical because electricity created during rotation of the cargo vessel can heat the fluid to drive the engine as the surrounding sea water cools the fluid to introduce a fast active thermo dynamic cycle. The inventor of this invention has already designed such a Heat Engine under the title "Compact Spindle Drive" Ser. No. 278,415. The engine activates the gear box to rotate the propeller shaft to propel the vessel, meaning the prime mover vessel operates the cargo vessel. In this fashion, no exhaust gases are involved as long as the heat source is generated from electricity or radio isotopic heat elements. Further objects and advantages of the invention will be apparent from the following description of the invention.